Ecosystem Ecology
Ecosystem
• All the organisms in a community plus abiotic factors
– Transform energy & process matter
• Ecosystems are self-sustaining
– what is needed?
capture energy
transfer energy
cycle nutrients
Ecosystem inputs
constant
energy flows
input
of
through
energy
nutrients cycle
How does energy
move through
the ecosystem?
biosphere
inputs
 energy
 nutrients
Energy flows through
ecosystems
sun
secondary
consumers
(carnivores)
primary consumers
(herbivores)
producers (plants)
loss of
energy
loss of
energy
Primary Productivity
• What is primary productivity?
• What is GPP?
• What is NPP?
• How does the light/dark bottle method allow
you to calculate primary productivity?
5
Limiting Factors
What are some
limiting Factors that
can effect
productivity?
Light
Nitrogen
Phosphorous
What is learned
from this data?
Food chains
• Trophic levels
–Why do food chains
usually go up only 4 or
5 levels?
–all levels connect to
decomposers
Level 4
Tertiary consumer
top carnivore
Level 3
Secondary consumer
carnivore
Level 2
Primary consumer
heterotrophs
herbivore
Level 1
Producer
autotrophs
Decomposers
Bacteria
Fungi
Inefficiency of energy transfer
• Loss of energy between levels of food chain
–Where is the energy that is not available to the next
tropic level?
17%
growth
only this energy
moves on to the
next level in
the food chain
energy lost to
daily living
33%
cellular
respiration
50%
waste (feces)
Ecological pyramid
• Loss of energy between levels of food chain
– can feed fewer animals in each level
1
100
100,000
1,000,000,000
Food webs
• Food chains are
linked together into
food webs
• Who eats whom?
–a species may weave
into web at more than
one level
• bears
• humans
–eating meat?
–eating plants?
Humans in food chains
• What has more energy a pound of hamburger or a pound of peas?
• What is the most efficient way for one person to eat?
• What is the most efficient way for the human population to eat?
Biological
Magnification
does
WhyWhere
do eggshells
Let’s go to the video!
the toxin
become
accumulate?
Fragile?
13
Nutrients…
nutrients cycle
Matter
cannot
Don’t forget
laws of or
bethe
created
Physics!
destroyed
biosphere
General
Nutrient
Cycle
consumer
consumer
s
consumer
producer
s
nutrients
nutrients
ENTER FOOD
CHAIN
made
available
= made
available
to producers
to producers
Decomposition
connects all
trophic levels
decomposer
decomposer
s
abiotic
abiotic
reservoi
reservor
r
geologic
geologic
processe
processe
s
return to
abiotic
reservoir
Carbon cycle
CO2 in
atmosphere
Diffusion
Respiration
abiotic reservoir:
CO2 in atmosphere
Other reservoir
Fossil fuels of fuels
Combustion
enter food chain:
photosynthesis
=
Industry and home
carbon fixation in Calvin
Photosynthesis
cycle
recycle:
decomposition
return to abiotic:
Plants
respiration
Animals
combustion
Dissolved CO2
Bicarbonates
Photosynthesis
Animals
Plants and algae
Carbonates in sediment
Deposition of
dead material
Deposition
of dead
material
Fossil fuels
(oil, gas, coal)
Nitrogen
cycle
Carnivores
abiotic reservoir:
N in atmosphere
Local reservoir N in soil
enter food chain:
nitrogen fixation by soil &
aquatic bacteria
recycle:
Herbivores
decomposing & nitrifying
bacteria
return to abiotic:
denitrifying bacteria
Birds
Plankton with
nitrogen-fixing
bacteria
Atmospheric
nitrogen
Plants
Death, excretion, feces
Fish
excretion
Decomposing bacteria
amino acids
Ammonifying bacteria
loss to deep sediments
Nitrogen-fixing
bacteria
(plant roots)
Nitrogen-fixing
bacteria
(soil)
Nitrifying bacteria
soil nitrates
Denitrifying
bacteria
abiotic reservoir:
surface & atmospheric
water
enter food chain:
precipitation & plant
uptake
recycle:
Solar energy
transpiration
return to abiotic:
Evaporationevaporation & runoff
Water cycle
Transpiration
Water vapor
Precipitation
Oceans
Runoff
Lakes
Percolation in soil
Groundwater
Aquifer
Transpiration
Phosphorus
cycle
Plants
Land
animals
Soluble soil
phosphate
Loss in
drainage
Rocks and
minerals
Decomposers Phosphates
(bacteria & fungi) in solution
Animal tissue
and feces
abiotic reservoir:
rocks, minerals, soil
enter food chain:
erosion releases soluble
phosphate
uptake by plants
recycle:
decomposing bacteria &
fungi
Animal tissue
abiotic:
Urinereturn
andto
feces
loss to ocean sediment
Decomposers
(bacteria and
fungi)
Aquatic
animals
Plants and
algae
Precipitates
Loss to deep sediment
Breaking the water cycle
• Deforestation breaks the water cycle
–groundwater is not transpired.
Precipitation is not created.
forest desert
desertification
Studying ecosystems
• Hubbard Brook
Experimental Forest
7800 acres
38 acre deforestation
Effects of deforestation
40% increase in runoff
loss of water
60x loss in nitrogen
10x loss in calcium
loss into
surface water
Concentration
of nitrate (mg/l )
80 nitrate levels in runoff
40
loss out of
ecosystem!
4
Deforestation
Why is nitrogen
so
2
Important?
0
1965
1966
1967
Year
1968
Rising CO2
Would this have
happened
without us?
24
Ozone Depletion
What did we do
this time?
25